CRC ERROR nrf5340

[emag nioj]

Hello, i have a custom board with lot of CRC ERRORS the same code, of course, works on the PDK. The spectrum transmission seems the same of the PDK.

Is it possible that the 32Mhz oscillator is the cause?

Is there a simple example to configure 125 Kbits  now i m using Nrf_1Mbit 

Is there a workaround reducing the speed or some other config parameter?  i need just to send few data

thank you!

emag

[ketiljo]

Can you post a schematic and the 32 MHz crystal spec please?

[emag nioj]

Hello, pin E31 VDD 1.8V is not connected there is a fault in the PCB. I m trying to rework.

on the PDK i have removed the track that connects E31 to the capacitor and the PDK started to have the same troubles.

if possible please confirm that a missing VDD on E31 can be the reason of CRC errors the other functionalities on the CPU are all ok.

if  E31 is the power supply of the internal oscillator, can i replace the external xtal with a 32MHz oscillator? it's only a prototype but i need it for my customer.

Thank you!
Emag

[ketiljo]

All the VDD pins are internally connected. But the connection on the die isn't strong enough to properly power the device completely. So the VDD supply are split into different pins. So one pin doesn't power a specific part of the device. You need to connect the PS to all VDD for proper operation. 

Most likely, there are parts of the radio power supply that are operating out of spec when you are missing power on pin E31.

[emag nioj]

Thank you, i m trying to rework the  prototype pcb connecting the E31 and preparing a new gerber..

Many thanks!

[emag nioj]

Hi Ketiljo, sorry to bother again. I reworked the custom board but i have always crc error troubles. Also other prototype boards are with same problem. Enabling the internal 8pF internal capacitors it seems a bit better but very random.

Connecting an external 32MHz signal from a generator one board started to work very well, but another one nope. The crystal is diigkey 1253-1586-1-ND

Please Let me know  where i can put the schematic possibly in a private way.

Many thanks,
Emag

[ketiljo]

The crystal you have is a 8 pF crystal (CL value). So the load caps should be 12 pF.

Ccap = CL * 2 -Cpin, where Cpin = 4 pF.

Given that it works with a generator, your crystal is probably not loaded correctly. This will pull the frequency and affect the radio.